1. Field of the Invention
The present invention relates to garments and other covers used to protect against microscopic or sub-microscopic contaminants, such as viruses.
2. Description of Related Art
Health care professionals and others are regularly exposed to a wide number of serious infectious microbes in their work places. While at one time face masks and gloves were provided to health care professionals primarily to protect patients from infection during operations, concerns about the health of both patients and workers has greatly expanded the use of such barriers today. As a result, many workers are now forced to wear protective gloves for long periods during their regular duties.
Conventional gloves made from silicone or other "rubber" elastomer have proven to be relatively good protective barriers. These products are quite impermeable to most contaminants and are inexpensive enough to be discarded after each use. However, rubber gloves have a number of deficiencies, including being impermeable to moisture vapor (making them very uncomfortable to wear for long periods of time), being subject to deterioration when exposed to certain chemicals or other adverse environmental conditions, and being prone to puncture and tears.
One answer to the uncomfortable nature of conventional rubber gloves is to employ gloves made from a waterproof and breathable material, such as expanded polytetrafluoroethylene (PTFE) made in accordance with U.S. Pat. No. 3,953,566 to Gore. Expanded PTFE as a membrane comprises a lattice of polymeric nodes and interconnected fibrils that creates an effective microporous barrier. This barrier repels water and other liquids while allowing moisture vapor to escape. More importantly for use in health care applications, a barrier of expanded PTFE has been demonstrated to be quite effective at isolating contaminants, such as microorganisms.
Gloves, glove inserts, masks and gowns made from expanded PTFE and fabric composites are commercially available under the trademark GORETEX from W. L. Gore & Associates, Inc., Newark, Del. For many uses these gloves are considered to be the state-of-the-art in waterproof/breathable protection. Despite their effectiveness in a wide variety of applications, it has now been determined that at least certain gloves made from this composite do not consistently pass certain tests for microbial protection. While these gloves are thoroughly waterproof through both the membrane and the seams, according to certain tests it has been determined that viruses can penetrate through these gloves. Further study has demonstrated that, although the composite material in these gloves does present a successful shield, surprisingly it is the seams of these gloves that are prone to virus leakage.
Conventional seams in expanded PTFE and fabric composites are generally formed by applying a bead of adhesive between fabric layers and sealing the seams together, sometimes under some elevated heat and pressure. Another approach in seam construction is to apply high heat and pressure to a polymeric coating so as to melt-flow and bond two layers together. Despite the effectiveness of these approaches in avoiding water penetration, it has been determined that these seams are not effective strong barriers to sub-microscopic contaminants, such as viruses suspended in a body fluid simulant (42.+-.2 dynes/cm).
Accordingly, it is a primary purpose of the present invention to provide an improved protective cover that is comfortable to wear yet provides an effective barrier to virus penetration.
It is a further purpose of the present invention to provide a protective cover that has seams that are resistant to virus penetration.
These and other purposes of the present invention will become evident from review of the following specification.